equiJoinCondition(String selector1Name,
String property1Name,
String selector2Name,
String property2Name)
Tests whether the value of a property in a first selector is equal to the
value of a property in a second selector.

sameNodeJoinCondition(String selector1Name,
String selector2Name,
String selector2Path)
Tests whether a first selector's node is the same as a node identified
by relative path from a second selector's node.